The grid is formed by the lines of constant width and longitude, built relative to the axis of rotation of the earth. Primary reference points are the poles at which the Earth`s axis of rotation intersects the reference surface. The planes containing the axis of rotation intersect the surface at the meridians; and the angle between a meridian plane and that of Greenwich (the prime meridian) defines longitude: meridians are lines of constant longitude. The plane passing through the center of the Earth and perpendicular to the axis of rotation intersects the surface in a large circle called the equator. Planes parallel to the equatorial plane intersect the surface in circles of constant width; These are the parallels. The equator has a latitude of 0°, the North Pole has a latitude of 90° North (written 90° N or +90°) and the South Pole has a latitude of 90° South (written 90° S or −90°). The latitude of any point is the angle between the equatorial plane and the normal to the surface at that point: the perpendicular to the surface of the sphere is along the radial vector. The length of a latitude is about 111 km (69 miles) and varies due to the unevenness of the earth`s curvature from 110.567 km (68.706 miles) at the equator to 111.699 km (69.41 miles) at the poles. Latitude lines, also called parallels, are imaginary lines that divide the Earth.

They go from east to west, but measure your distance to the north or south. The equator is the best known parallel. At 0 degrees latitude, it divides the Earth evenly into the northern and southern hemispheres. From the equator, latitude increases as you travel north or south, reaching 90 degrees at each pole. The distance in meters (correct at 0.01 meters) between latitudes φ {displaystyle phi } − 0.5 degrees and φ {displaystyle phi } + 0.5 degrees on the spheroid WGS84 is An example of the use of authalic latitude is the Albers equal cone projection. [9]: §14 Parametric latitude or reduced latitude β is defined by the radius drawn from the center of the ellipsoid at point Q on the surrounding sphere (radius a), which is the projection parallel to the Earth`s axis of a point P on the ellipsoid at φ. latitude. It was introduced by Legendre[11] and Bessel,[12] who solved the problems of geodesists on the ellipsoid by transforming them with this smaller latitude into an equivalent problem for spherical geodesists. Bessel`s notation u(φ) is also used in the current literature. Parametric latitude is related to geodetic latitude by:[6][7] There are six auxiliary latitudes that have applications to specific problems in geodesy, geophysics, and map projection theory: Each latitude covers about 111 kilometers on the Earth`s surface. A latitude can be divided into 60 minutes and one minute further into 60 seconds.

One second of latitude is only about 30.7 meters. Unlike the lines of longitude, which approach the poles, the lines of latitude are parallel. No matter where you are on Earth, the lines of latitude are equidistant from each other. Latitude, as defined in this way for the sphere, is often referred to as spherical latitude to avoid ambiguity with the geodesic latitude and auxiliary latitudes defined in the following sections of this article. Longitude and longitude, a coordinate system that can be used to determine and describe the position or location of any location on the earth`s surface. Latitude is a measurement on a globe or map of the location north or south of the equator. Technically, there are different types of latitude – geocentric, astronomical and geographical (or geodesic) – but there are only minor differences between them. In most common references, geocentric latitude is implicit. Expressed in degrees, minutes and seconds, geocentric latitude is the arc subtled by an angle at the center of the Earth and measured towards the pole from the equator in a north-south plane. Thus, a period at . (100 words out of 525) As there are many different reference ellipsoids, the exact latitude of a feature on the surface is ambiguous: this is emphasized in the ISO standard, which states that „without the complete specification of the coordinate reference system, coordinates (i.e. latitude and longitude) are at best ambiguous and at worst meaningless“.

This is of great importance in specific applications, such as a global positioning system (GPS), but in general use where high accuracy is not required, the reference ellipsoid is usually not specified.